In this work, a collection of 94 Macrophomina isolates obtained from roots of two weed species, Trianthema portulacastrum and Boerhavia diffusa, collected during surveys conducted during 2015 and 2016 in melon production fields in Northeastern Brazil, were characterized by using molecular techniques. Phylogenetic analysis of the EF1‐α gene allowed the identification of 32 isolates as M. phaseolina and 62 isolates as M. pseudophaseolina. Results of a pathogenicity test performed on melon seedlings of the cv. “Gladial” revealed that all M. phaseolina isolates inoculated were able to cause disease to melon seedlings, but only some M. pseudophaseolina isolates were able to infect them. This study represents the first report of M. pseudophaseolina in both T. portulacastrum and B. diffusa weeds, which are prevalent in the main Brazilian melon producing and exporting regions. Information about the biology and epidemiology of M. pseudophaseolina is scarce because of its recent description; thus, further research is needed for a better understanding of this fungus as a potentially emerging pathogen of melon and other crops.

One of the main diseases that reduces production of passion fruit crops is Fusarium wilt, caused by the fungus Fusarium oxysporum f.sp. passiflorae (FOP). The use of resistant rootstocks, such as the species Passiflora cincinnata, is one of the management strategies used to control this disease. The objective of this work was to evaluate the pathogenicity of different isolates of FOP on P. edulis and P. cincinnata in order to identify its potential for use in areas with a history of the disease. Thirteen isolates of the fungus were used, and the inoculums were produced at a concentration of 106 CFU/ml. Seedlings were produced in coconut fibre, and the root system was then immersed for five minutes in the conidial suspension before being replanted in the 770‐ml pots. Inoculated seedlings of P. edulis and P. cincinnata at the three‐leaf stage were daily evaluated from the second day after inoculation (DAI) until day 90. All isolates were pathogenic in both Passiflora species; however, the incidence, severity and mortality were higher in P. edulis. There was a statistically significant difference for the incubation period of the FOP 23 and FOP 57 isolates, being higher in P. edulis. We concluded that P. cincinnata was susceptible to FOP.

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Macrophomina pseudophaseolina is a new Macrophomina species reported on different crop and weed species in Brazil, India and Senegal, but to date there are no studies about its adaptability components. In this work a collection of 62 M. pseudophaseolina isolates obtained from roots of the weed species Trianthema portulacastrum and Boerhavia diffusa collected in Northeastern Brazil, was used to: i) study the effect of temperature and salinity on mycelial growth, ii) to determine their sensitivity to the fungicide carbendazim, and iii) to assess their aggressiveness on melon and watermelon seedlings. Results showed variability among M. pseudophaseolina isolates. The optimum temperature for mycelial growth ranged between 26.4 and 38.1ºC.NaCl reduced the in vitro growth of all isolates, which were also highly sensitive to the fungicide carbendazim, exhibiting EC50 values ranging from 0.013 to 0.089 mg L -1 a.i.Disease severity values on melon and watermelon seedlings showed that M. pseudophaseolina isolates were more aggressive in melon than in watermelon.Information about adaptability components of M. pseudophaseolina obtained in this study could be incorporated on breeding programs for melon and watermelon crops.

Seeds of ‘sabiá’ (Mimosa caesalpiniifolia Benth.) have coat dormancy, which hampers the absorption of water and oxygen, thereby delaying germination. Thus, this study aimed to evaluate methods for overcoming dormancy associated with priming on germination and vigor of seeds of ‘sabiá’, considering the efficiency, practicality and cost of treatment. The experimental design was completely randomized, in a 4 x 5 factorial scheme (four methods for overcoming dormancy x five types of priming), constituting 20 treatments with four replicates of 25 seeds. The methods for overcoming dormancy used were tip removal, seed immersion in hot water at 100 °C for three minutes, immersion in sulfuric acid for 10 minutes and intact seeds. For the determination of physiological conditioning of seeds, the imbibition curve with the different priming agents was constructed. Priming was done on filter paper moistened with solutions of mannitol at the potentials of -0.2 MPa (16 hours), -0.4 MPa (24 hours) and -0.6 MPa (36 hours) and only with distilled water for the hydropriming (12 hours) and seeds without priming. The variables analyzed were first count of germination, germination, root length, shoot length and dry weight of seedlings. The data were subjected to analysis of variance by F test and Tukey test at 5% probability. The dormancy of M. caesalpiniifolia seeds should be overcome with the use of hot water (100 °C) for three minutes, without the need for priming.